title: The Gm--Pi linkage heterogeneity in view of Pi M subtypes.
abstract: In this study linkage between the loci for Gm (gamma-type heavy-chain immunoglobulin markers) and Pi (alpha 1-antitrypsin/alpha 1-protease inhibitor) has been shown in families segregating for the Pi M subtypes (M1, M2, M3 and Msal) as identified by separator isoelectric focusing . The estimate for the Gm--Pi (M type) recombination is 0.29 (95% limits 0.24--0.37) at a peak lod score of 4.31 and with no sex difference. This value is not significantly different from updated recombination frequency estimates for Gm--Pi in Pi MS (0.26) and Pi MZ, SZ and FZ families (0.21). The overall Gm--Pi recombination fraction estimate of 0.26 (95% limits 0.23--0.30) at a peak lod score of 20.75 must now be considered as solid. There is a significant heterogeneity within the male Pi MZ families in that the new Finnish families show a higher recombination between Gm and Pi. There is also a possible segregation distortion (Z:M = 23:8). The heterogeneity is discussed in terms of haplotypes, the behaviour of which could be determined by linked genes or chromosomal rearrangements. The possibility that the alpha 1-antitrypsin level influences recombination frequency has not been ruled out, but cannot explain the heterogeneity within Pi MZ families.
mesh_terms: D000483:Alleles; D005260:Female; D005809:Genes, Regulator; D008040:Genetic Linkage; D005819:Genetic Markers; D006579:Heterozygote; D006801:Humans; D007126:Immunoglobulin Allotypes / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007142:Immunoglobulin gamma-Chains / Q000235:genetics*; D007525:Isoelectric Focusing; D008297:Male; D010641:Phenotype; D011995:Recombination, Genetic; D000515:alpha 1-Antitrypsin / Q000235:genetics; D019896:alpha 1-Antitrypsin Deficiency
chemical_list: D005819:Genetic Markers; D007126:Immunoglobulin Allotypes; D007143:Immunoglobulin Heavy Chains; D007142:Immunoglobulin gamma-Chains; D000515:alpha 1-Antitrypsin